﻿Shader "Custom/PixelCube"
{
    Properties
    {
        _Color ("Color", Color) = (1,1,1,1)
        _MainTex ("Albedo (RGB)", 2D) = "white" {}
        _Glossiness ("Smoothness", Range(0,1)) = 0.5
        _Metallic ("Metallic", Range(0,1)) = 0.0
        _ScaleAndOffset("缩放与偏移", Vector) = (1,1,0,0)
        _Scale("Scale", Float) = 1
    }
    SubShader
    {
        Tags { "RenderType"="Opaque" }
        LOD 200

        CGPROGRAM
        // Physically based Standard lighting model, and enable shadows on all light types
        #pragma surface surf Standard fullforwardshadows vertex:vert

        // Use shader model 3.0 target, to get nicer looking lighting
        #pragma target 3.0

        sampler2D _MainTex;

        struct Input
        {
            float2 uv_MainTex;
            float3 worldPos;
            float4 vertex;
        };

        void vert (inout appdata_full v, out Input i)
		{
			UNITY_INITIALIZE_OUTPUT(Input, i);
            i.vertex = v.vertex;
        }

        half _Glossiness;
        half _Metallic;
        fixed4 _Color;
        half4 _ScaleAndOffset;
        half _Scale;

        // Add instancing support for this shader. You need to check 'Enable Instancing' on materials that use the shader.
        // See https://docs.unity3d.com/Manual/GPUInstancing.html for more information about instancing.
        // #pragma instancing_options assumeuniformscaling
        UNITY_INSTANCING_BUFFER_START(Props)
            // put more per-instance properties here
        UNITY_INSTANCING_BUFFER_END(Props)

        void surf (Input IN, inout SurfaceOutputStandard o)
        {
            float ColorNoiseWidth = _ScaleAndOffset.x;
            float ColorNoiseHeight = _ScaleAndOffset.y;
            float ColorNoiseCenterX = _ScaleAndOffset.z;
            float ColorNoiseCenterY = _ScaleAndOffset.w;

            float3 positionWS = IN.worldPos - IN.vertex.xyz * _Scale;
            positionWS.x = positionWS.x - ColorNoiseCenterX + ColorNoiseWidth * 0.5;
            positionWS.y = positionWS.y - ColorNoiseCenterY + ColorNoiseHeight * 0.5;
            positionWS.x /= ColorNoiseWidth;
            positionWS.y /= ColorNoiseHeight;

            // Albedo comes from a texture tinted by color
            fixed4 c = tex2D (_MainTex, positionWS.xy) * _Color;
            o.Albedo = c.rgb;
            // Metallic and smoothness come from slider variables
            o.Metallic = _Metallic;
            o.Smoothness = _Glossiness;
            o.Alpha = c.a;
        }
        ENDCG
    }
    FallBack "Diffuse"
}
